1. Field of the Invention
The present invention relates generally to a method of managing forwarding tables of network processors, and more particularly to a method of managing forwarding tables of network processors based on address learning in a line card of an Ethernet system having a plurality of network processors and a multiplexing/demultiplexing module, and a computer readable storage medium for storing a program for executing the method, which reduces the number of times network processors must access forward tables to one by adjusting a plurality of address learning results, thus reducing the number of instances of entry update and entry deletion in forwarding tables to one.
2. Description of the Prior Art
In general, a forwarding table of an Ethernet system that provides a bridge function is generated by a process of learning addresses. The address learning process adds a source address of an Ethernet data frame and the information of a port, through which the Ethernet data frame is received, to a forwarding table as a meaningful entry for aging time. If the same data frame is not received for the aging time, the entry is deleted from the forwarding table.
A line card of the Ethernet system exploits network processors to provide a high-speed forwarding function. An address learning process is performed in each of the network processors, and various information managed in the network processors is integrated by a main processor and transmitted to the network processors from the main processor.
However, a system, which is capable of providing a large band interface by connecting a plurality of network processors providing small bands and a multiplexing/demultiplexing module, is problematic in that overhead required to manage forwarding tables results from multiple address learning processes in a line card when a forwarding entry is generated. In particular, due to the overhead of excessive address learning processes, the entries of the forwarding table are frequently updated and deleted, so it is difficult to effectively manage the forwarding table.
U.S. Pat. No. 6,236,654 B1 discloses a method and apparatus for effectively managing an address table to generate frame forwarding information in a switch where address learning processes are performed through multiple ports. That is, this patent utilizes an address table to generate frame forwarding information in a network switch configured to switch data packets across multiple ports. If a forwarding entry decision engine does not find a match, the network switch adds an entry to the address table using a source address of a received data frame and a port number on which the data frame is received. The new entry is used to generate frame forwarding information in subsequent searches of the address table. However, this patent provides a normal address learning method in a line card using a single chip, and cannot solve the above-described problems. That is, this patent does not provide a method of performing a multiple number of instances of entry update and entry deletion in a plurality of network processors at one time in the same manner as in a line card using a single chip.